I came across a database of mutagens in cooked food (mutagens occur
mostly in meat and fish cooked at high temperature). See

http://www-bio.llnl.gov/mutagens/html/mutagen.frame.html

To make interpretations easier, I extracted the following data:

For beefsteak (sirloin) fried 3.5 minutes/side, the amount of the
mutagen PhIP, expressed in nanograms per grams of cooked food, as a
function of temperature, is

  temperature    amount of PhIP
  (degrees C)       (ng/g)
--------------------------------
    150            0.06-0.1
    175            0.02-0.7
    200            1.2 -6.3
    225            1.8 -5.3

(A range, instead of a single number, is given because different
experiments got different results.)

We can see that the amount of mutagens rises dramatically with
temperature. Cooking at 200 degrees C instead of 150 degrees C
increases the amount of mutagens at least 10-fold.

Now, for fried salmon (at 200 degrees C):

  cooking time   amount of PhIP
 (min per side)     (ng/g)
--------------------------------
       3            1.7
       6           23
       9           14
      12           17

And BBQed salmon (at 270 degree C):

  cooking time   amount of PhIP
 (min per side)     (ng/g)
--------------------------------
       3            2
       6            6.2
       9           69
      12           73

Again, results may not be very accurate, but we see that cooking 12
minutes instead of 3 minutes increases the amount of mutagens at least
10-fold, and that in general, BBQed meat contains considerably more
mutagens than fried foods (since typical frying temperatures are 150-200
degrees C, and BBQing temperatures 250-300 degrees C).

Finally, we note that most data involve foods cooked at 150 degree C
or higher, the reason being that mutagens don't appear in significant
amounts at lower temperatures (e.g. boiled meat). According to the
database, stewed chicken (100 degrees C) has no detectable amounts of
mutagens.

Remark: there are many other mutagens than PhIP, but results would be
similar.

--Jean-Louis Tu <[log in to unmask]>


P.S.
    degree C   degree F
------------------------
      100        212
      150        302
      175        347
      200        392
      250        482
      270        518
      300        572

P.P.S. 1 Euro    = 1.15$
       1 Euro/kg = 0.5 $/lb. This should make conversions easier...